Half to the gould



'0! T. LEE.

INSULATOR. I I

Patented Feb. 2, 1892.

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(ha ML, wuzm UNITED STATES PATENT OFFICE,

CHARLES TENNANT LEE, OF BOSTON, MASSACHUSETTS, ASSIGNOR OF ONE- HALF TO THE GOULD dz \VATSON COMPANY, OF SAME PLACE.

- INSULATOR.

SPECIFICATION forming part of Letters Patent No. 467,942, dated. February 2, 1892.

Application filed November 11, 1891- Serial No. 411,566. (No model.)

To aZZ whom it may concern.-

Be it known thatI, CHARLES TENNANT LEE, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massach usetts,haveinvented certain new and useful Improvements in Insulators, of which the following is a specificatiomreference being had therein to the accompanying drawing.

My invention has for its object to produce a strong and durable insulator chiefly for use for electrical purposes, although, as will be obvious, it may also I be employed as a heatinsulator. It consists of a metallic casing which contains within it an insulated metallic rod, the insulation being effected by means of sheets of mica laid and pressed together, and the inclosing portion of the metallic shell or casingbeing constructed in one piece, all as hereinafter set forth, and the novel features of which are more particularly pointed out in the claims, which are appended hereto.

My invention is shown in the accompanying drawing in the best form now known to me. Said drawing shows a trolleywire hanger in vertical section.

A represents a casing or shell, which is of metal formed in one piece and having a cylindrical body. The precise cross sectional shape of the body is not material, although the circular form is preferred. 1) represents lugs'or projections by means of which, in case the device is used as a trolley-wire hanger, it may be secured or supported.

d is a rod by which the clip f, which is secured to the trolley, is supported. The rod 61 terminates in a button or head, which serves to prevent the rod from being withdrawn. A number of sheets of mica g, which have first been cut into the right shape to fit the interior of the caseA and which have been provided with a central aperture through which the rod d may pass, are strung upon the rod, the quantity of mica used being sufficientto fillthe body of the bell or case A. The space at the crown of the case A and surrounding the head of the bolt 01 may, if desired, be filled with flake mica or mica in small pieces or scales. The end of the rod d which projects from the case A is screw-threaded to receive the clip which holds the trolley-wire, and that portion of the rod between the clip and the mica 9 within the case is covered or partially covered by a series of sheets of mica 72, of smaller diameter than the sheets of mica g. Said sheets h have a central aperture through them and are strung on the rod (1. These washers of mica h insulate the projecting portions of the rod d, so that the distance between the uncovered 6o metallic parts is largely increased compared with what it would be if the stem was not so protected. A retaining nut 3' may be screwed onto the rod d, as shown, to keep the sheets of mica h in place. After the sheets 65 of mica g are placed on the rod 01 they are inserted in the case A, and they may be retained in the case by short projections 70, which are secured at intervals to the month of the hell or case A and which are turned down, as shown, against the mica g after the mica is inserted in the case, or instead of the projections it a ring or projecting edge of the case A may be turned down against the sheets of mica to retain them within the case, the latter form of construction being preferable because it is stronger.

For the purpose of shedding moisture when the insulator is employed as a hanger a skirt wt, preferably of metal, may be connected So with the case A, preferably by being formed integral therewith, as shown.

I am aware that trolley-wire hangers have been made having the case which is supported by the cross-wires insulated from the stem which supports the clip by sheets of mica; but such insulators, so far as known to me, haveemployed a shank or stem with a head larger than the aperture or opening in the metallic portion of the hell or case, which necessitated dividing the hell or caseinto two portions, thus increasing the expense of construction, rendering the case liable to admit moisture, and impairing its strength and efficiency.

lVhat I claim is- 1. An insulator comprising an outer case and a rod or stem placed within the said case and insulated therefrom by a series of sheets of mica and having that portion of the stem :00

which projects beyond the mica in the case 9, the said case having retaining projections partially covered by a series of sheets of is turned down, Substantially as shown and mica placed thereon, substantiallyas set forth. described.

2. An insulator comprising an outer case A, In testimony whereof I ailix my signature in 5 constructed in onepiece,anda rod or stem (1, presence of two witnesses.

placed Within the said case and insulated therefrom by a series of sheets of mica, the CHARLES said rod or stem having the portion thereof \Vitnesses: which projects beyond the mica in the case 7 M. A. MAOLEOD,

IO partially covered bya series of sheets of mica ROBERT WALLACE. 

